Phthalic anhydride production system

Abstract

The utility model provides a phthalic anhydride production system which successfully solves the problem that residual materials at the bottom of a phthalic anhydride buffer tank cannot be completely emptied by reasonably designing pipelines and valve configuration. Specifically, a third pipeline is arranged in the system, is connected to an outlet in the bottom of the buffer tank and is provided with a first control valve, so that residual phthalic anhydride materials at the bottom of the buffer tank can be completely emptied through the pipeline in the production process; therefore, the problem that the phthalic anhydride quality is influenced by long-time shutdown or oxidation of residual materials in a traditional system is effectively avoided. Through the design, not only are the continuity and the stability of the phthalic anhydride production process improved, but also the quality of a final product is guaranteed, and the quality fluctuation problems of phthalic anhydride color value increase and the like are avoided. Meanwhile, the system simplifies operation, reduces manual intervention and improves production efficiency.

Description

Technical Field

[0001] This utility model relates to the technical field of phthalic anhydride production equipment, specifically to a phthalic anhydride production system. Background Technology

[0002] Phthalic anhydride is an important chemical raw material widely used in plasticizers, unsaturated polyester resins, dyes, and pharmaceuticals. Common industrial phthalic anhydride production processes include the o-xylene oxidation method and the naphthalene oxidation method, with key processes involving raw material oxidation reaction, condensation separation, material storage, and packaging. The production quality of phthalic anhydride (especially the stability of its color value) and the flexibility of its operating procedures are key factors affecting its market competitiveness. Therefore, the optimization of phthalic anhydride production facilities is one of the research hotspots in the chemical industry.

[0003] In traditional phthalic anhydride production plants, the produced phthalic anhydride is typically transferred to a finished product tank (or intermediate tank) for storage, and then pumped to a packaging machine for packaging. However, this existing technology has the following design features and technical problems:

[0004] In the subsequent processes of phthalic anhydride production, buffer tanks are typically used to temporarily store liquid phthalic anhydride between the finished product tank and the packaging machine, providing stable flow and pressure during packaging. Buffer tanks are designed with their outlet lines typically positioned a certain distance from the tank bottom (e.g., 50 cm) to prevent impurities from the tank bottom from entering the outlet line, thus protecting the pumps and machinery. While this height prevents impurities from entering the pipeline, it inevitably leads to a certain amount of phthalic anhydride residue at the bottom. During prolonged shutdowns, this residual phthalic anhydride readily comes into contact with air, undergoing an oxidation reaction that increases the phthalic anhydride color value, affecting the quality of subsequent products. The accumulation of residue at the bottom can also increase the frequency and difficulty of tank cleaning, reducing equipment efficiency. When it's necessary to change products or clean the tank, the residual material at the bottom cannot be quickly discharged using the existing design, resulting in inefficient replacement operations. Especially when product quality fluctuates, the inability to quickly empty the tank can lead to mixing of old and new materials, further affecting product stability and consistency.

[0005] In existing technologies, phthalic anhydride buffer tanks suffer from the technical problem of not being able to completely empty the residual material at the bottom of the tank. This technical problem not only leads to unstable color values ​​in phthalic anhydride products, affecting product quality, but also increases the complexity of production operations and maintenance costs. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a phthalic anhydride production system to solve the technical problem that the phthalic anhydride buffer tank cannot completely empty the residual material at the bottom of the tank in related technologies.

[0007] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, this utility model provides a phthalic anhydride production system, comprising:

[0009] Buffer tanks are used to store liquid phthalic anhydride;

[0010] Finished product tanks are used to store liquid phthalic anhydride;

[0011] Packaging equipment for packaging liquid phthalic anhydride;

[0012] The first pump is used to transfer liquid phthalic anhydride from the finished product tank to the buffer tank;

[0013] A second pump is used to deliver liquid phthalic anhydride from the buffer tank to the packaging device;

[0014] The first pipeline has one end connected to the outlet of the first pump and the other end connected to the inlet of the buffer tank.

[0015] The second pipeline has one end connected to the middle outlet of the buffer tank and the other end connected to the inlet of the second pump.

[0016] The third pipeline has one end connected to the bottom outlet of the buffer tank and the other end connected to the inlet of the second pump; wherein the third pipeline is equipped with a first control valve.

[0017] Furthermore, the second pipeline is equipped with a filter device for filtering impurities in the liquid phthalic anhydride.

[0018] Furthermore, the phthalic anhydride production system also includes:

[0019] A second control valve is configured on the first pipeline near the inlet of the buffer tank.

[0020] Furthermore, the phthalic anhydride production system also includes:

[0021] The fourth pipeline has one end connected to the outlet of the second pump and the other end connected to the first pipeline, and is connected between the outlet of the first pump and the inlet of the second control valve.

[0022] The third control valve is located in the fourth pipeline.

[0023] Furthermore, the phthalic anhydride production system also includes:

[0024] Intermediate tank, which is used to store crude phthalic anhydride;

[0025] The fifth pipeline has one end connected to the inlet of the intermediate tank and the other end connected to the first pipeline, and is connected between the outlet of the first pump and the connection point between the fourth pipeline and the first pipeline.

[0026] The fourth control valve is located in the fifth pipeline.

[0027] Furthermore, the intermediate tank is made of stainless steel and has an anti-corrosion coating on its inner surface.

[0028] Furthermore, a quick-connect interface is provided at the connection between the fifth pipeline and the intermediate tank.

[0029] Furthermore, the third pipeline is equipped with a backflow prevention valve.

[0030] Furthermore, the first and second pumps are centrifugal pumps, piston pumps, gear pumps, or screw pumps.

[0031] Furthermore, the first control valve is an electric valve, a manual valve, a hydraulic valve, or a pneumatic valve.

[0032] Beneficial effects:

[0033] The phthalic anhydride production system provided by this invention successfully solves the problem of incomplete emptying of residual material from the bottom of phthalic anhydride buffer tanks through a rationally designed pipeline and valve configuration. Specifically, the system incorporates a third pipeline connected to the bottom outlet of the buffer tank and equipped with a first control valve. This pipeline allows for the complete emptying of residual phthalic anhydride material from the bottom of the buffer tank during production, effectively preventing the quality issues caused by residual material affecting phthalic anhydride quality due to prolonged downtime or oxidation, as is common in traditional systems. This design not only improves the continuity and stability of the phthalic anhydride production process but also ensures the quality of the final product, preventing quality fluctuations such as increased phthalic anhydride color value. Furthermore, the system simplifies operation, reduces manual intervention, and improves production efficiency. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of a phthalic anhydride production system provided in an embodiment of this utility model;

[0035] Figure 2 This is a schematic diagram of a phthalic anhydride production system provided in an embodiment of this utility model;

[0036] In the attached image:

[0037] Buffer tank: 101;

[0038] Finished product cans: 102;

[0039] Packaging equipment: 103;

[0040] First pump: 104;

[0041] Second pump: 105;

[0042] First control valve: 106;

[0043] Second control valve: 107;

[0044] Third control valve: 108;

[0045] Intermediate tank: 109;

[0046] Fourth control valve: 1010. Detailed Implementation

[0047] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0048] like Figure 1 This embodiment provides a phthalic anhydride production system, including:

[0049] Buffer tank 101 is used to store liquid phthalic anhydride.

[0050] In this embodiment, the buffer tank 101 may include a tank body, which may be made of a corrosion-resistant material (such as stainless steel) to ensure that phthalic anhydride does not react with the tank body during storage. The exterior of the tank body may be coated with an anti-corrosion coating to extend its service life. The tank body may be cylindrical or elliptical to ensure uniform liquid distribution and prevent the accumulation of precipitates. The inlet of the tank body may be located at the top of the tank body for receiving liquid phthalic anhydride from the finished product tank 102 or other pretreatment units. The tank body may have multiple outlets, including a central outlet located in the middle of the tank body and a bottom outlet located at the bottom of the tank body. The central outlet is used to send the liquid phthalic anhydride to the next stage of processing, while the bottom outlet is used to discharge residual materials (such as phthalic anhydride precipitates or impurities).

[0051] In this embodiment, both the inlet and outlet of the tank can be equipped with valves, such as electric valves, pneumatic valves, or manual valves, to control the flow rate and discharge of the liquid. These valves can be remotely controlled or manually controlled on-site to adjust the flow rate during production.

[0052] In this embodiment, to accurately control the storage volume of liquid phthalic anhydride, a level gauge can be installed on the buffer tank 101. These level gauges can be float level gauges, pressure level gauges, or ultrasonic level gauges, which monitor the liquid level in real time to ensure that the phthalic anhydride in the tank remains within the specified range.

[0053] In this embodiment, the inside of the tank may be provided with a cleaning port and a spray system for periodically cleaning the inside of the tank.

[0054] In this embodiment, the bottom of the tank can be equipped with a stabilizing support device to ensure that the tank is stable and does not tilt. Metal brackets or support legs can be used to ensure the stability and safety of the buffer tank 101.

[0055] Finished product tank 102 is used to store liquid phthalic anhydride.

[0056] In this embodiment, the finished product tank 102 may also include a tank body, which may also be made of a corrosion-resistant material (such as stainless steel) to ensure that phthalic anhydride does not react with the tank body during storage. The exterior of the tank body may also be coated with an anti-corrosion coating to extend its service life. The tank body may also be cylindrical or elliptical to ensure uniform liquid distribution and prevent the accumulation of sediment.

[0057] In this embodiment, the finished product tank 102 may also include an inlet and an outlet. Specifically, the inlet of the finished product tank 102 may be connected to a pre-processing unit, such as the outlet of a switching condenser. The outlet of the finished product tank 102 is connected to the inlet of the buffer tank 101 via a first pump 104 and a first pipeline. Phthalic anhydride in the finished product tank 102 flows into the pipeline through the outlet and is drawn by the first pump 104 into the buffer tank 101. Through the configuration of the pump and pipeline, phthalic anhydride can be efficiently and safely transported from the finished product tank 102 to the buffer tank 101, providing a stable material supply for the subsequent packaging process.

[0058] Packaging device 103 is used for packaging liquid phthalic anhydride.

[0059] In this embodiment, the packaging device 103 may be an automated filling machine.

[0060] In this embodiment, the packaging device 103 may be a piston filling machine.

[0061] In this embodiment, the packaging device 103 may be a gravity filling machine.

[0062] In this embodiment, the packaging device 103 may be a screw capping and filling machine.

[0063] In this embodiment, the packaging device 103 may be a flow meter filling machine.

[0064] The first pump 104 is used to transfer liquid phthalic anhydride from the finished product tank 102 to the buffer tank 101.

[0065] In this embodiment, the inlet of the first pump 104 is connected to the outlet of the finished product tank 102, and the outlet of the first pump 104 is connected to the first pipeline.

[0066] In this embodiment, the first pump 104 may be a centrifugal pump, a piston pump, a gear pump, or a screw pump.

[0067] The second pump 105 is used to deliver liquid phthalic anhydride from the buffer tank 101 to the packaging device 103.

[0068] In this embodiment, the inlet of the second pump 105 can be connected to the middle outlet of the buffer tank 101 via a second pipeline, and the inlet of the second pump 105 can also be connected to the bottom outlet of the buffer tank 101 via a third pipeline.

[0069] The outlet of the second pump 105 can be connected to the packaging device 103 via a discharge pipeline.

[0070] In this embodiment, the second pump 105 may be a centrifugal pump, a piston pump, a gear pump, or a screw pump.

[0071] The first pipeline has one end connected to the outlet of the first pump 104 and the other end connected to the inlet of the buffer tank 101.

[0072] In this embodiment, the first pipeline may be a stainless steel pipeline.

[0073] In this embodiment, the first pipeline may be a polyethylene pipeline (PE pipe).

[0074] In this embodiment, the first pipeline may be a polypropylene pipeline (PP pipe).

[0075] In this embodiment, the first pipeline can be a fiberglass reinforced plastic (FRP) pipe.

[0076] The second pipeline has one end connected to the middle outlet of the buffer tank 101 and the other end connected to the inlet of the second pump 105.

[0077] In this embodiment, the second pipeline may be a stainless steel pipeline.

[0078] In this embodiment, the second pipeline may be a polyethylene pipeline (PE pipe).

[0079] In this embodiment, the second pipeline can be a polypropylene pipeline (PP pipe).

[0080] In this embodiment, the second pipeline can be a fiberglass reinforced plastic (FRP) pipe.

[0081] The third pipeline has one end connected to the bottom outlet of the buffer tank 101 and the other end connected to the inlet of the second pump 105; wherein the third pipeline is equipped with a first control valve 106.

[0082] In this embodiment, the third pipeline can be a stainless steel pipeline.

[0083] In this embodiment, the third pipeline may be a polyethylene pipeline (PE pipe).

[0084] In this embodiment, the third pipeline can be a polypropylene pipeline (PP pipe).

[0085] In this embodiment, the third pipeline can be a fiberglass reinforced plastic (FRP) pipe.

[0086] In this embodiment, the first control valve 106 may be an electric valve, a manual valve, a hydraulic valve, or a pneumatic valve.

[0087] Understandably, the first pump 104 is responsible for conveying liquid phthalic anhydride from the finished product tank 102 to the buffer tank 101. The first pump 104 draws phthalic anhydride from the finished product tank 102 and sends it into the buffer tank 101 via a first pipeline. The buffer tank 101 serves as an intermediate storage device to ensure the stable operation of subsequent production processes. The phthalic anhydride stored in the buffer tank 101 is then sent to the packaging device 103 for packaging via the second pump 105. The phthalic anhydride is conveyed from the middle outlet of the buffer tank 101 through a second pipeline to the inlet of the second pump 105, and then from the second pump 105 through a pipeline to the packaging device 103, completing the packaging process. To address the issue of residual material at the bottom of the buffer tank 101 not being emptied, this embodiment incorporates a third pipeline. One end of this pipeline is connected to the bottom outlet of the buffer tank 101, and the other end is connected to the inlet of the second pump 105. Through this pipeline, the system can extract and discharge residual phthalic anhydride from the bottom of buffer tank 101 via the second pump 105, preventing oxidation of the phthalic anhydride due to prolonged shutdown. A first control valve 106 is installed in the third pipeline; adjusting the opening and closing of this valve controls whether the phthalic anhydride at the bottom of buffer tank 101 is emptied. When it is necessary to empty the residual material at the bottom, the control valve is opened and the pump is started to discharge the material, ensuring that no phthalic anhydride remains in buffer tank 101 and preventing any impact on subsequent production.

[0088] The phthalic anhydride production system provided in this embodiment successfully solves the problem of incomplete emptying of residual material at the bottom of the phthalic anhydride buffer tank 101 by rationally designing pipelines and valve configurations. Specifically, the system is equipped with a third pipeline connected to the bottom outlet of the buffer tank 101 and fitted with a first control valve 106. This pipeline allows for the complete emptying of residual phthalic anhydride material at the bottom of the buffer tank 101 during production, effectively avoiding the problem of residual material affecting phthalic anhydride quality due to prolonged downtime or oxidation, as is common in traditional systems. This design not only improves the continuity and stability of the phthalic anhydride production process but also ensures the quality of the final product, preventing quality fluctuations such as increased phthalic anhydride color value. Furthermore, the system simplifies operation, reduces manual intervention, and improves production efficiency.

[0089] In some embodiments, the second pipeline is provided with a filter device for filtering impurities in liquid phthalic anhydride.

[0090] In this embodiment, the filtering device may be a mesh filter.

[0091] In this embodiment, the filtration device may be a multi-media filter.

[0092] In this embodiment, the filtration device may be an activated carbon filter.

[0093] In this embodiment, the filtration device may be a centrifugal filter.

[0094] In this embodiment, the filter device can be located in the middle of the second pipeline, or directly disposed inside the second pipeline. Alternatively, one end of the second pipeline can be connected to the middle outlet of the buffer tank 101, and the other end can be connected to the inlet of the filter device. The outlet of the filter device is connected to the other end of the second pipeline, ensuring that the filtered liquid phthalic anhydride can continue to flow to the second pump 105 and finally be delivered to the packaging device 103. The liquid phthalic anhydride flows into the filter device through the second pipeline, and impurities in the liquid are effectively removed when passing through the filter medium. The filtered liquid phthalic anhydride continues to flow along the pipeline and finally enters the second pump 105 for use by the subsequent packaging device 103.

[0095] In this embodiment, the filtration device configured in the second pipeline effectively removes impurities from liquid phthalic anhydride, ensuring that the phthalic anhydride reaches the required purity and quality standards before being delivered to the packaging unit 103. Real-time filtration prevents impurities from entering the packaging unit 103 or affecting subsequent production processes, thereby improving the quality stability of the phthalic anhydride product. Furthermore, the filtration device reduces wear on pipes and pumps, extends equipment lifespan, and lowers maintenance costs. Overall, the filtration device improves the operational efficiency and safety of the production system, ensuring quality control of phthalic anhydride during storage, transportation, and packaging.

[0096] like Figure 2 As shown, in some embodiments, the phthalic anhydride production system further includes:

[0097] The second control valve 107 is configured at the position of the first pipeline near the inlet of the buffer tank 101.

[0098] In this embodiment, the second control valve 107 may be an electric valve, a manual valve, a hydraulic valve, or a pneumatic valve.

[0099] In this embodiment, the second control valve 107 is positioned near the inlet of the first pipeline close to the buffer tank 101, enabling precise control of the flow rate of liquid phthalic anhydride from the finished product tank 102 into the buffer tank 101. By adjusting the opening and closing of this control valve, precise regulation of the phthalic anhydride flow rate can be achieved, thereby optimizing the storage and distribution process of phthalic anhydride in the buffer tank 101. This configuration effectively prevents too much or too little liquid from entering the buffer tank 101, avoiding problems such as liquid pressure buildup or poor flow, and ensuring the stability and efficiency of the production process. Simultaneously, the second control valve 107 also provides convenient operation when the system needs to switch or adjust the flow rate, improving the system's automated control capabilities and response speed, reducing the complexity of manual operation, and enhancing the reliability and safety of the production process.

[0100] In some embodiments, the phthalic anhydride production system further includes:

[0101] The fourth pipeline has one end connected to the outlet of the second pump 105 and the other end connected to the first pipeline, and is connected between the outlet of the first pump 104 and the inlet of the second control valve 107.

[0102] The third control valve 108 is configured in the fourth pipeline.

[0103] In this embodiment, the configuration of the fourth pipeline and the third control valve 108 enhances the operational flexibility and fluid control precision of the phthalic anhydride production system. By connecting the fourth pipeline between the outlet of the second pump 105 and the first pipeline, and configuring the third control valve 108 thereon, the system can more effectively regulate the flow direction and flow rate of liquid phthalic anhydride. Specifically, the third control valve 108 allows the system to selectively guide liquid phthalic anhydride from the second pump 105 to the first pipeline, or to other parts, as needed, avoiding misflow or unnecessary backflow of the liquid. Furthermore, the configuration of the fourth pipeline provides flexibility for multi-path flow of the liquid, further improving the operational efficiency and accuracy of the entire system. Through this optimized design, the phthalic anhydride production system can better regulate liquid flow under different operating conditions, reduce energy consumption, and improve the stability and safety of the production process.

[0104] In some embodiments, the phthalic anhydride production system further includes:

[0105] Intermediate tank 109 is used to store crude phthalic anhydride;

[0106] The fifth pipeline has one end connected to the inlet of the intermediate tank 109 and the other end connected to the first pipeline, and is connected between the outlet of the first pump 104 and the connection point between the fourth pipeline and the first pipeline.

[0107] The fourth control valve 1010 is configured in the fifth pipeline.

[0108] In this embodiment, the configuration of the intermediate tank 109, the fifth pipeline, and the fourth control valve 1010 further optimizes the material storage and flow control of the phthalic anhydride production system. By using the intermediate tank 109 to store crude phthalic anhydride and connecting it to the first pipeline via the fifth pipeline, the system can flexibly transfer a portion of the phthalic anhydride to the intermediate tank 109 for storage. The configuration of the fourth control valve 1010 in the fifth pipeline allows operators to precisely control the flow direction of the phthalic anhydride, selectively directing it from the finished product tank 102 into the buffer tank 101 or from the finished product tank 102 into the intermediate tank 109, thereby optimizing the storage of phthalic anhydride.

[0109] Understandably, by controlling the fourth control valve 1010, phthalic anhydride can be directly guided from the finished product tank 102 to the intermediate tank 109 when needed, effectively reducing the waste of phthalic anhydride, while ensuring that crude phthalic anhydride can be specially stored, providing a more stable supply for subsequent processing.

[0110] Understandably, intermediate tank 109, as a storage unit for crude phthalic anhydride, can mitigate the impact of phthalic anhydride flow fluctuations on production, while also making phthalic anhydride storage more flexible and ensuring sufficient material supply at different production stages.

[0111] Understandably, when there is residual material at the bottom of buffer tank 101, the operator can open the first control valve 106 and the fourth control valve 1010, simultaneously start the second pump 105, open the third control valve 108, and close the second control valve 107 and the first pump 104. In this way, the residual phthalic anhydride material will be drawn into the second pump 105 through the third pipeline, and then enter the fourth pipeline. Since the second control valve 107 is closed at this time, the residual material cannot enter buffer tank 101, and the first pump 104 is also closed to prevent it from flowing into the finished product tank 102. Simultaneously, the fourth control valve 1010 remains open, ensuring that the material can enter the fifth pipeline through the first pipeline and be transported to the intermediate tank 109, which is used to store crude phthalic anhydride. This configuration ensures that residual material in the phthalic anhydride production process can be efficiently recovered, avoiding waste and improving material utilization in the production process. Furthermore, this flexible piping and valve control setup enhances the automation level and production efficiency of the entire system, ensures the quality stability of phthalic anhydride, and reduces operational complexity.

[0112] In some embodiments, the intermediate tank 109 is made of stainless steel and has an anti-corrosion coating on its inner surface.

[0113] In this embodiment, the intermediate tank 109 is made of stainless steel, and its inner surface is coated with an anti-corrosion coating, which effectively improves the corrosion resistance and durability of the phthalic anhydride production system. Stainless steel provides excellent mechanical strength and temperature resistance, enabling it to withstand certain pressure and temperature changes during phthalic anhydride storage and transportation. The anti-corrosion coating effectively prevents phthalic anhydride from reacting with the tank, preventing contamination or quality degradation during storage. This design not only extends the service life of the intermediate tank 109 but also ensures that phthalic anhydride maintains its purity and stability during storage, improving the safety and reliability of the entire production system.

[0114] In some embodiments, a quick-connect interface is provided at the connection between the fifth pipeline and the intermediate tank 109.

[0115] In this embodiment, a quick-connect interface is provided at the connection between the fifth pipeline and the intermediate tank 109, which significantly improves the operational efficiency and maintenance convenience of the phthalic anhydride production system. The quick-connect interface allows operators to quickly connect and disconnect pipelines when needed, without the need for complex tools or lengthy operations. This design not only simplifies the system's installation and maintenance process, saving significant time, especially during pipeline cleaning or replacement, but also improves production flexibility and responsiveness. Through the quick-connect interface, the phthalic anhydride production system can perform equipment switchover and maintenance more efficiently, reducing downtime and improving overall production efficiency.

[0116] In some embodiments, the third pipeline is provided with a backflow prevention valve.

[0117] In this embodiment, a backflow prevention valve is installed in the third pipeline. This valve effectively prevents liquid phthalic anhydride from flowing back into the pipeline. When pressure fluctuations occur in the system or the pump stops working, the backflow prevention valve automatically closes, preventing the phthalic anhydride from flowing backward and thus ensuring fluid stability. This design prevents phthalic anhydride from flowing into areas it should not enter at inappropriate times, such as buffer tank 101 or finished product tank 102, preventing cross-contamination or affecting subsequent production processes. In addition, the use of the backflow prevention valve improves system safety, reduces equipment damage or product quality fluctuations caused by fluid backflow, and further enhances the reliability and stability of the production process.

[0118] In some embodiments, the first pump 104 and the second pump 105 are centrifugal pumps, piston pumps, gear pumps, or screw pumps.

[0119] In some embodiments, the first control valve 106 is an electric valve, a manual valve, a hydraulic valve, or a pneumatic valve.

[0120] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0121] Optionally, specific examples in this embodiment can refer to the examples described in the above embodiments, and will not be repeated here.

[0122] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0123] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0124] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A phthalic anhydride production system, characterized in that, include: Buffer tanks are used to store liquid phthalic anhydride; Finished product tanks are used to store liquid phthalic anhydride; Packaging equipment for packaging liquid phthalic anhydride; The first pump is used to transfer liquid phthalic anhydride from the finished product tank to the buffer tank; A second pump is used to deliver liquid phthalic anhydride from the buffer tank to the packaging device; The first pipeline has one end connected to the outlet of the first pump and the other end connected to the inlet of the buffer tank. The second pipeline has one end connected to the middle outlet of the buffer tank and the other end connected to the inlet of the second pump. The third pipeline has one end connected to the bottom outlet of the buffer tank and the other end connected to the inlet of the second pump; wherein the third pipeline is equipped with a first control valve.

2. The system according to claim 1, characterized in that, The second pipeline is equipped with a filter device for filtering impurities in liquid phthalic anhydride.

3. The system according to claim 1, characterized in that, The phthalic anhydride production system also includes: A second control valve is configured on the first pipeline near the inlet of the buffer tank.

4. The system according to claim 3, characterized in that, The phthalic anhydride production system also includes: The fourth pipeline has one end connected to the outlet of the second pump and the other end connected to the first pipeline, and is connected between the outlet of the first pump and the inlet of the second control valve. The third control valve is located in the fourth pipeline.

5. The system according to claim 4, characterized in that, The phthalic anhydride production system also includes: Intermediate tank, which is used to store crude phthalic anhydride; The fifth pipeline has one end connected to the inlet of the intermediate tank and the other end connected to the first pipeline, and is connected between the outlet of the first pump and the connection point between the fourth pipeline and the first pipeline. The fourth control valve is located in the fifth pipeline.

6. The system according to claim 5, characterized in that, The intermediate tank is made of stainless steel and has an anti-corrosion coating on its inner surface.

7. The system according to claim 5, characterized in that, The connection between the fifth pipeline and the intermediate tank is equipped with a quick-connect interface.

8. The system according to any one of claims 1-7, characterized in that, The third pipeline is equipped with a backflow prevention valve.

9. The system according to any one of claims 1-7, characterized in that, The first pump and the second pump are centrifugal pumps, piston pumps, gear pumps, or screw pumps.

10. The system according to any one of claims 1-7, characterized in that, The first control valve is an electric valve, a manual valve, a hydraulic valve, or a pneumatic valve.

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